Exceptional condition for such a rare part! This is the Type 3 Oil pump body with the OEM number 678-41A. Page 264 of the Palmer's How To Restore your HARLEY-DAVIDSON Volume One. As stated in the book, this is the one that does not have the stepped-down by-pass valve.
The item "Genuine Harley Knucklehead Oil Pump 1946-1947 Only OEM 678-41A TYPE 3 Knuckle" is in sale since Thursday, October 28, 2021. This item is in the category "eBay Motors\Parts & Accessories\Motorcycle Parts\Antique, Vintage, Historic". The seller is "pirate6095" and is located in Lockport, New York. This item can be shipped worldwide.